Bottom hole shut-in tool

ABSTRACT

AN ELONGATE MANDREL ADAPTED TO BE SUSPENDED IN A TUBULAR WELL CONDUIT BY A WIRE LINE EXTENDS THROUGH AN UPPER ASSEMBLY SECTION WHICH INCLUDES AN INTERNALLY SLOTTED CONTROL SLEEVE SECURED TO THE UPPER END OF A TUBULAR MOUNTING MEMBER. AN INSULATED ELECTRICAL CONDUCTOR EXTENDS THROUGH THE MANDREL FOR MONITORING OR CONTROLLING ELECTRICAL EQUIPMENT SECURED BELOW THE MANDREL AND THE MOUNTING MEMBER CARRIES RADIALLY EXPANDABLE LOCKING SLIPS AT ITS LOWER END. LEAF SPRINGS ARE SECURED EXTERNALLY OF THE MOUNTING MEMBER TO PROVIDE A FRICTION DRAG AGAINST THE SURROUNDING WELL CONDUIT WHICH HOLDS THE MEMBER STATIONARY WHILE THE MANDREL IS MOVED AXIALLY. A SHORT KNOB EXTENDS RADIALLY FROM THE MANDREL AND ENGAGES INTERCONNECTED SLOT AND STOPS FORMED IN THE CONTROL SLEEVE TO SELECTIVELY TRANSMIT AXIAL MOVEMENT OF THE MANDREL TO THE UPPER ASSEMBLY. A MIDDLE ASSEMBLY SURROUNDING THE MANDREL INCLUDES A CENTRALLY APERTURED CONICAL SLIP SPREADER SECURED TO A SLOTTED TUBULAR BODY WHICH IN TURN IS SECURED TO A DOWNWARDLY OPENING PACKER CUP. A LOWER ASSEMBLY CARRIED OVER THE MANDREL INCLUDES A TUBULAR VALVE SLEEVE WHICH IS SEALED ABOUT THE MANDREL WITH A SLIDING O-RING SEAL. A CONICAL CUP SPREADER FORMED AT THE BOTTOM OF THE LOWER ASSEMBLY ENGAGES A BACKUP BODY SECURED TO THE LOWER END OF THE MANDREL. THE MIDDLE AND LOWER ASSEMBLY ARE SECURED TO THE MANDREL BY SHEAR PINS WHICH ARE SEQUENTIALLY SEVERED DURING THE SETTING AND RETRIEVAL MOTIONS. RASISING THE   MANDREL THROUGH THE APPROPRIATE CHANNEL IN THE SLOTTED PATHWAY ENGAGES THE SLIP SPREADER AND SLIPS TO EXPAND THE SLIPS AND ANCHOR THE UPPER ASSEMBLY. SUBSEQUENT RAISING SHEARS THE PIN SECURING THE UPPER ASSEMBLY TO THE MANDREL AND ENGAGES THE PACKER SPREADER AND PACKER TO EXPAND THE PACKER. THE VALVE SLEEVE AND PACKER COOPERATE TO SEAL THE WELL CONDUIT. MOVING THE MANDREL DOWNWARDLY OPENS A BYPASS CHANNEL BETWEEN THE MANDREL AND THE VALVE SLEEVE TO EQUALIZE PRESSURE ACROSS THE SET PACKER. FURTHER DOWNWARD MOVEMENT OF THE MANDREL PERMITS THE PACKER AND SLIPS TO RETRACT AND RELEASE THE TOOL FROM THE WELL CONDUIT. CONTINUED LOWERING AND SUBSEQUENT RAISING OF THE MANDREL ENGAGES THE MANDREL KNOB IN A CONTROL SLEEVE STOP AND THE ENTIRE TOOL ASSEMBLY MAY BE LIFTED FROM THE CONDUIT. THE ENTIRE TOOL MAY BE REVERSED IN THE CONDUIT FOR USE WITH HIGHER PRESSURES ABOVE THE PACKER. THE LOWER ASSEMBLY MAY ALSO INCLUDE A HOUSING WITH SPACED O-RING SEALS WHICH SURROUND AND ENGAGE THE MANDREL SECTIONAL AREAS ENGAGING THE SEALS TO BALANCE AXIALLY DIRECTED FORCES EXERTED ON THE MANDREL CAUSED BY THE PRESSURE DIFFERENTIAL EXISTING ACROSS THE SET PACKER OR TO PRODUCE A NET UPWARDLY OR DOWNWARDLY DIRECTED FORCE DEPENDING UPON THE RELATIVE DIMENSIONS OF THE VARIOUS SEALING AREAS.

United States Patent [72] inventor Arthur L. Owen Houston, Tex.

[21] Appl. No. 854,174

[22] Filed Aug. 29, 1969 [45] Patented June 28, 1971 [73] Assignee Electric Wireline Specialties, Inc.

Alice, Tex.

[54} BOTTOM HOLE SHUT-IN TOOL Primary ExaminerJames A. Leppink Attorney-Carlos A. Torres ABSTRACT: An elongate mandrel adapted to be suspended in a tubular well conduit by a wire line extends through an upper assembly section which includes an internally slotted control sleeve secured to the upper end of a tubular mounting member. An insulated electrical conductor extends through the mandrel for monitoring or controlling electrical equipment secured below the mandrel and the mounting member carries radially expandable locking slips at its lower end. Leaf springs are secured externally ofthe mounting member to pro- IID vide a friction drag against the surrounding well conduit which holds the member stationary while the mandrel is moved axially. A short knob extends radially from the mandrel and engages interconnected slot and stops formed in the control sleeve to selectively transmit axial movement of the mandrel to the upper assembly. A middle assembly surrounding the mandrel includes a centrally apertured conical slip spreader secured to a slotted tubular body which in turn is secured to a downwardly opening packer cup. A lower assembly carried over the mandrel includes a tubular valve sleeve which is sealed about the mandrel with a sliding O-ring seal. A conical cup spreader fonned at the bottom of the lower assembly engages a backup body secured to the lower end of the mandrel. The middle and lower assembly are secured to the mandrel by shear pins which are sequentially severed during the setting and retrieval motions. Raising the mandrel through the appropriate channel in the slotted pathway engages the slip spreader and slips to expand the slips and anchor the upper assembly. Subsequent raising shears the pin securing the upper assembly to the mandrel and engages the packer spreader and packer to expand the packer. The valve sleeve and packer cooperate to seal the well conduit. Moving the mandrel downwardly opens a bypass channel between the mandrel and the valve sleeve to equalize pressure across the set packer. Further downward movement of the mandrel permits the packer and slips to retract and release the tool from the well conduit. Continued lowering and subsequent raising of the mandrel engages the mandrel knob in a control sleeve stop and the entire tool assembly may be lifted from the conduit. The entire tool may be reversed in the conduit for use with higher pressures above the packer.

The lower assembly may also include a housing with spaced O-ring seals which surround and engage the mandrel to form a sealed chamber. The mandrel has different cross-sectional areas engaging the seals to balance axially directed forces exerted on the mandrel caused by the pressure differential existing across the set packer or to produce a net upwardly or downwardly directed force depending upon the relative dimensions of the various sealing areas.

PMENTEU 'JUN28 ism SHEET 2 OF 3 Arthur L. Owen- IN VENTOR ATTORNEY BOTTOM HOLE SHUT-IN TOOL l. Field of the Invention The present invention relates generally to means for forming an internal seal in a tubular conduit. In the specific examples hereinafter described, the field of the present invention is that of tools for forming a subsurface seal in casing, tubing and other conduits employed in oil and gas wells.

2. Brief Description of the Prior Art A variety of tools have been disclosed and employed for sealing oil and gas well conduits at a subsurface location. Such devices are generally suspended from a wire line or tubing string and employ slips or anchoring means designed to expand and engage the surrounding well conduit to set the tool in the desired subsurface location. Where a pressure seal is required, such tools are also equipped with a resilient packer which may be radially expanded to engage and seal against the surrounding tubing walls.

Because of the relatively great pressures existing in oil and gas formations, a substantial pressure differential may exist across the seal formed by the set packer which tends to axially displace the tool in the conduit. As a result, the slips and packer of the tool must be securely engaged against the-conduit walls to prevent such displacement and to maintain the required seal. For this reason, the tool components are generally designed to wedge more tightly together as the pressure differential across the packer increases which in turn more firmly anchors the tool in place by increasing the radially directed forces exerted by the slips and packer against the well conduit. I

Where the tools of the'type being considered are designed to be retrieved from the conduit after having been set and sealed, it is necessary to separate the wedged tool components to permit the slips and packer to retract radially away from the tubing wall. Such separation however is extremely difficult or even impossible to effect where the pressure drop across the packer is relatively great and the tool components are firmly wedged together under the influence of the pressure differential. In many cases, both the tool and the well conduit are damaged during attempts to release the tool by overcoming the forces created by the pressure differential existing across the tool components. Moreover, where sensitive well testing equipment is secured to the tool, such equipment may be easily damaged by the pounding or jarring required to release the tool from the well conduit.

In the foregoing situation, it is often necessary to apply pressure above the tool until the pressure differential across the packer has been reduced sufficiently to permit separation of the tool components as required for retraction of the slips and packer. Conversely, when the greatest pressure exists above the tool, it is often necessary to bleed off pressure at the well head until the pressure differential across the tool has been reduced sufficiently to permit release of the slips and packer.

To overcome the necessity of increasing or decreasing the pressure in the well conduit before releasing a set tool, the prior art has suggested the use of a bypass valve in the tool body which could be opened prior to release of the slips and packer to thereby permit equalization of the pressure across the packer. Certain of such prior art pressure bypass mechanisms known to the applicant are however relatively difficult to open, undependable operation and often require relatively elaborate components.

Another shortcoming associated with many of the prior art tools is their limited usefulness. Such tools are generally designed for a single specific use such as for forming a subsurface seal in a conduit where the pressure below the tool is to be greater than that above the tool. If the pressure above the plug is to be greater than that below, it is often necessary to extensively modify the tool or employ an altogether different tool for such purpose. It may also be desirable to suspend equipment below the tool for various purposes such as testing of the formation pressure both while the well is flowing and while it is shut-in. In some cases it may be necessary to plug the well conduit, completely release the tool and thereafter retrieve the tool. While only' a few examples of specific requirements for shutin tools have been given, many different needs for such tools exist in the testing, treatment and production of oil and gas wells and for each of such needs, a different prior art shutin tool has often been required.

SUMMARY OF THE INVENTION The present invention relates to a wire line operated shutin tool of the type having expandable metal slips and a resilient packer designed to be anchored internally of a tubular conduit to form a pressure seal. The tool of the present invention is provided with a pressure bypass means which permits pressure equalization across the packer before the tool is released from its set position.

The tool includes an elongate, generally cylindrical mandrel having several reduced diameter sections formed along its length and an insulated electrical conductor extending axially through its center. An upper assembly surrounds the upper portion of the mandrel and includes a control sleeve secured to the upper end of a tubular mounting member. Radially expandable slips are secured to the lower end of the mounting member and drag-springs are secured to its outer surface. The internal surface of control sleeve is provided with a pathway formed by a series of interconnected channels and stops which receive and guide a knob extending radially from the mandrel.

The central portion of the mandrel is surrounded by a conical slip spreader secured to a longitudinally slotted tubular body which in turn is secured to a downwardly opening, resilient packer cup. The lower portion of the mandrel is surrounded by a valve sleeve having a conical cup spreader formed at its lower end. An O-ring forms a seal between the upper end of the valve sleeve and an enlarged diameter segment of the mandrel. The slip spreader and cup spreader assemblies are each secured to the mandrel by shear pins to prevent premature movement between these components. A backup plug is permanently secured to the lower end of the mandrel in engagement with the cup spreader to transmit upwardly directed mandrel movements to the cup spreader and valve sleeve.

When the tool is suspended in a well conduit, the drag springs on the upper assembly engage the surrounding well conduit to hold the assembly stationary as the mandrel is moved through the control sleeve. By appropriately lowering and raising the mandrel through the control sleeve, the mandrel knob is placed in a longitudinal setting channel which permits the mandrel to be raised without also raising the upper assembly. Initial raising of the mandrel relative to the upper assembly draws the conical slip spreader under the slips to radially expand and securely anchor the upper assembly against the well conduit. Continued raising of the mandrel shears the pin securing the mandrel to the slip spreader and draws the valve sleeve and cup spreader under the packer cup to expand and seal the cup against the well conduit. The outer surface of the valve sleeve seals with an O-ring carried internally of the cup assembly and cooperates with the O-ring seal between the mandrel and sleeve to completely seal the well conduit.

In retrieving the tool, the mandrel is moved downwardly, shearing the pin securing it to the cup spreader and disengaging the O-ring seal between the mandrel and valve sleeve to open a pressure bypass channel between the mandrel and the sleeve which permits equalization of the pressure differential across the packer. Relatively little force is required to open the pressure bypass because of the relatively small cross-sectional area of the seal formed between the mandrel and the sleeve. When the pressure differential across the packer has been sufficiently reduced, the mandrel is lowered further to force the cup spreader assembly out from under the cup permitting the cup to retract radially away from the surrounding conduit. Continued mandrel lowering separates the slip,

spreader and slips to permit retraction of the slips and completely release the tool. The tool may then be withdrawn from the well conduit by raising the mandrel and mandrel knob into engagement with a stop in the control sleeve path to draw the entire tool assembly with the mandrel.

In a modification of the invention, a force altering chamber is employed to alter the normally existing pressure induced forces exerted on the mandrel when the tool has been set in the well conduit. By this means, the pressure bypass may be released with little or no application of external force to the mandrel thus preventing damage to the tool and any instruments secured thereto.

In applications where the pressure above the packer is to be the greatest, the lower end of the mandrel is secured to the wire line suspension and the tool is then inverted and lowered into the well conduit, no modification or alteration of the tool being required. The setting and retrieving operations for the inverted tool are similar to those previously described except in a reverse direction.

From the foregoing it may be appreciated that the bottom hole shutin tool of the present invention is capable of being anchored and released without the need for externally applied pressure equalization across the sealed packer. As will become more evident from the following description, the specific means employed to equalize pressure across the set packer is of simple construction and is dependable in its operation. The pressure bypass of the present invention permits the use of relatively small retrieving forces resulting in prolonged tool life and minimizing the possibility of damaging the well conduit. In the modified form of the invention, the force altering means alters the effect of pressure induced force acting on the mandrel to balance or bias the mandrel in either axial direction when the conduit is sealed.

The tool is prevented from prematurely setting by means of the shear pins connecting relatively movable tool components while the setting sequence itself ensures anchoring of the slips before sealing of the packer to prevent the tool from skipping through the conduit as it is being set. Similarly, the retrieval sequence of the tool causes release of the packer before release of the slips to prevent the tool from being blown through the well conduit by any pressure differential which may exist across the packer.

Various electrical equipment may be suspended below the set tool with the electrical pathway across the length of the tool permitting continuous monitoring or control of such equipment from the well surface. If desired, the tool may be set in a desired subsurface location and the connecting wire line may be pulled free of the tool and withdrawn from the well conduit. Subsequent retrieval of the set tool may then be accomplished by latching any suitable fishing device over an enlargement formed at the top of the mandrel. The retrieval procedure may then be effected in the previously described manner.

While a variety of applications and features of the bottom hole shutin tool of the present invention have already been described, these and other aspects of the invention will be more fully understood and appreciated from the following specification, the related drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are longitudinal sections of the upper and lower portions respectively of one form of the tool of the present invention illustrating the tool suspended in an unset condition within a well conduit;

FIG. 2 is a lateral cross section on an enlarged scale taken along the line 2-2 of FIG. 1;

FIG. 3 is a partial elevation of a portion of the control sleeve employed at the upper end of the tool illustrating an internally formed slot path;

FIG. 4 is a partial longitudinal section, partially developed, illustrating the lower portion of the tool of FIG. 1 with slips set;

FIG. 5 is a partial longitudinal section illustrating the lower portion of the tool of FIG. 1 with slips and packer set;

FIG. 6 is a partial longitudinal section illustrating the lower portion of the tool of FIG. 1 with the pressure bypass valve open;

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A and 1B illustrate the op and bottom portions respectively of the bottom hole shutin tool of the present invention, indicated generally at 10, suspended in a tubular well conduit C by means of a wire line W. The tool 10 includes an elongate central mandrel 11 formed in two threadedly connected segments 11a and 11b. A resilient O-ring 12 of rubber or other suitable material is positioned between the two segments to seal moisture away from the internal components of the mandrel and prevent inadvertent separation of the segments. An upper assembly 13 surrounds the mandrel 11 and includes a tubular control sleeve 14 threadedly secured to a sleeve 15 having a plurality of circumferentially spaced longitudinal slots 15a. The slots 15a are for the purpose of permitting sand or other fine particles entering the top of control sleeve 14 to exit the tool and thereby prevent clogging of the tool components. The lower end of the sleeve 15 in turn is threadedly secured to a mounting sleeve 16. A plurality ofcircumferentially spaced, longitudinally extending, resilient leaf springs 17 are externally secured to the mounting sleeve 16 by means of metal screws 18 and are employed to engage and slide along the internal walls of the well conduit C to create a friction drag tending to hold the upper assembly stationary with respect to the conduit.

A slip subassembly 19 is secured to the mounting sleeve 16 by means sealing of a first slip retaining member 20 which includes a first component 20a threadedly secured to the lower end of sleeve 16 and a second component 20b threadedly engaged about the first component 200. A plurality of slip members 21 are retained in the retaining member 20 by an annular channel formed between the components 20a and 20b which receives one end of each slip member 21. Radial projections 21b extend from each slip member 21 into slots formed in retaining component 20b to axially retain the slips within the member 20. The slip members 21 include laterally extending teeth 21c designed to engage and lock against the wall of the conduit C. An inwardly tapering surface 21d is formed on the internal portion of each slip member for a purpose to be hereinafter described. A discontinuous, circular metal spring 22 surrounds and extends through lateral slots formed in each of the slip members 21 biasing them to the radially retracted position illustrated in FIG. 1.

The central portion of the mandrel 11 is surrounded by a middle assembly 23 which includes a sleeve 24 threadedly secured to a conical slip spreader 25 which in turn is threadedly secured to a longitudinally slotted sleeve 26. A shear pin 26b extends through the sleeve 26 and into the mandrel 11 to fix the axial position of the middle assembly 23 with respect to the mandrel. The sleeve 24 includes slots 26a and is disposed between the slip subassembly l9 and the mandrel 11 where it is retained even after severance of the pin 26 by a radial enlargement 24a formed at the upper end of the sleeve. The enlargement 24a is adapted to engage the upper axial end of retaining component 20a to hold it in the desired relationship.

A packer cup subassembly 27 is secured to the lower end of the sleeve 26 and includes a mounting segment 28 threadedly engaged with the sleeve 26. A retaining cap 29 is threadedly positioned over the segment 28 and is employed to secure a.

downwardly opening, resilient packer cup 30 to the subassembly 27. The internal surface of the segment 28 is provided with an annular groove which carries a resilient O-ring seal 31 for a purpose to be hereinafter described.

With reference to FIG. 2, it may be seen that the retaining cap 29 includes a first set of circumferentially spaced longitudinally extending fingers 290 which surround a second set of similar fingers 29b. The spacing between the internal fingers 29b is overlapped by the external fingers 29a to permit radial expansion of the retaining cap 29 and packer 30 during setting of the tool while simultaneously preventing extrusion of the packer material.

Referring to FIG. 1B, the lower end of the mandrel 11 is surrounded by a bottom assembly 32 including a valve sleeve 33 having radial ports 33a and 33b with the sleeve 33 being enlarged at its lower end to form a conical packer cup spreader 34. A shear pin 34a secures the bottom assembly to the man drel 11 to prevent any premature movement between the pinned components. A resilient O-ring seal 35 disposed within an annular groove formed on a radially enlarged section 116 of the mandrel 11 forms a seal with the internal surface of the valve sleeve 33 to form a portion of the pressure bypass means ofthe tool 10.

Downward axial movement of the packer spreader 34 relative to the mandrel 11 is limited to a backup body 36 which is threadedly engaged with threads formed at the lower mandrel end. A resilient O-ring 37 is disposed between the mandrel and backup body 36 to seal moisture away from the internal components of the mandrel and to prevent inadvertent separation of the threaded connection. The lower portion of the backup body 36 is provided with external threads 36a to which testing or control equipment E may be secured.

With joint reference to FIGS. 1A and 18, an electrical con ductor 38 having insulation 38a extends through the central portion of the mandrel 11 and includes suitably insulated electrical connectors such as the plugs 38b and receptacles 38c which are employed to connect adjacent conductors across joints in the mandrel 11 and to provide electrical connection with a suitable conductor carried in the wire line W and with the electrical equipment E suspended from the backup body 36. The external dimensions of the mandrel 11 are varied in accordance with the teachings of the present invention to form upper and lower shoulders 11d and lle, respectively, for releasing the tool from its set position in the manner to be hereinafter described. The upper mandrel section 11a includes a short, radially projecting knob llfwhich extends into a slotted pathway 14a formed in the surrounding control sleeve 14.

The configuration of the control sleeve pathway 14a may best be described by reference to FIG. 3 which illustrates the course of the internal pathway in dotted lines. The pathway 140 includes a first longitudinal slot 14b extending downwardly to a diagonal slot 140 which in turn communicates with a first stop position 14d. Directly above the stop 14d is a second longitudinal slot 14:: extending upwardly to a diagonal slot 14f which terminates at a second stop position 14g. A short, downwardly extending, slanted slot 14h commu nicates with a third stop position 14i directly below an upwardly extending, slanted slot l4j which connects back to the slot 14b. The mandrel knob llf is moved through the slotted pathway 140 during the setting and retrieval of the tool in a manner to be hereinafter described.

With the basic construction and components of the tool having been set forth, an example of its application in an oil or gas well will now be described to provide a better understanding of the operation and various features and advantages of the tool. Where the pressure of the subsurface formation is to be tested, an appropriate pressure transducer represented by the equipment E is secured to the lower end of the mandrel l1 and the tool and transducer may then be lowered into the well conduit C with the slips 21 and packer 30 being in the fully retracted positions illustrated in FIGS. 1A and 18. Weight bars (not illustrated) are normally connected into the wire line suspension above the mandrelll to force the tool 10 and equipment E downwardly against the restraining force exerted against the conduit C by the compressed drag springs 17. During the initial lowering procedure, the mandrel knob 11f remains in the stop 14d or 141'.

When the desired subsurface location has been reached, the wire line W is sequentially raised and lowered as required depending upon whether the knob llf is at stop 14d or 141 to position the knob in control sleeve slot 14b. During this raising and lowering sequence, relative movement between the mandrel 11 and control sleeve 14 is possible because of the frictional engagement of the drag springs 17 against the internal walls of the well conduit C which function to hold the entire upper assembly 13 stationary during the initial portions of the setting procedure. The movement of mandrel 11 through the stationary assembly 13 is transmitted through the shear pins 26b to the middle assembly 23 and when knob 11f is in slot 14b, the mandrel knob 11f may be raised to the extent required axially above stop position 14g to draw the slip spreader 25 into engagement with the stationary slips 21. As the mandrel is thus raised, the tapered under surfaces 21d of the slips are forced over the conical outer surface of the advancing spreader 25 causing the slips to move radially outwardly against the restraining force of the spring 22 and into engagement with the surrounding well conduit C.

The initial anchoring of the slips is illustrated in FIG. 4. 1ncreased lifting forces exerted on the mandrel 11 when it is in the position illustrated in FIG. 4 securely anchors the slips 21 against the well conduit C and eventually severs the shear pins 26b securing the middle assembly to the mandrel. The mandrel 11 may thereafter be raised through both the upper and middle assemblies with such upward movement being transmitted by the backup body 36 to draw the lower assembly 32 into engagement with the stationary packer cup subassembly As best illustrated in FIG. 5, the continued upward movement of the mandrel l1 draws the valve sleeve 33 through the central opening of the packer cup 30 and permits the cup spreader 34 to engage and radially expand the packer into sealing contract with the well conduit C. When the tool components are in the relative positions illustrated in H6. 5, the well conduit C is completely sealed by means of the expanded packer 30, O-ring 31 and O-ring 35. The increasing pressure developed below the tool 10 tends to force the mandrel l 1 upwardly to increase the radially directed anchoring forces exerted against the well conduit C. Once the conduit has been thus sealed, increases or variations in pressure below the tool 10 may be detected by the equipment E and monitored at the well surface. Where a self-contained recording unit is employed as the equipment E, or when otherwise necessary or desired, the wire line assembly may be pulled free of the tool 10 and withdrawn from the well conduit. 1n the latter event, the frictional engagement of the tool components and the anchoring effect due to the pressure differential across the packer 30 hold the tool in position until such time as it is to be released and retrieved with the aid of a suitable fishing too].

With the wire line assembly W in place and after the desired information has been acquired, the tool 10 is retrieved by initially moving the mandrel ll downwardly with jars or other suitable means (not illustrated) connected into the wire line suspension. The frictional engagement formed between the cup spreader 34 and the packer 30 cooperates with the pressure induced force acting on the seal to resist separation of the two components. Sufficient downwardly directed forces will however shear the pins 34a to permit the mandrel to move downwardly through the lower assembly 32. Relatively little force is required to thus release the mandrel 11 since only the pressure forces acting against the relatively small sealing area circumscribed by the O-ring 35 need be overcome.

As illustrated in FIG. 6, lowering of the mandrel 11 through the spreader 34 and sleeve 33 moves the O-ring seal 35 out of engagement with the internal surface of the sleeve 33 to open a pressure bypass channel across the set packer 30. By this means, the pressure differential across the tool 10 is equalized in that fluids or gasses in the high-pressure area below the packer 30 are permitted to travel upwardly through the central bore of the valve sleeve and spreader assembly and exit through the radial bores 33b and slots 26a above the packer 30.

After the pressure differential across the tool has been sufficiently reduced, the mandrel 11 is lowered until the shoulder lle engages the upper axial end of the valve sleeve 33. The jars or other means of the wire line assembly are then em ployed to impart a downwardly directed force on the mandrel which is transmitted to the sleeve 33 causing the cup spreader 34 to move downwardly out of engagement with the packer 30. With the spreader thus removed, the packer 30 retracts radially to completely disengage the well conduit. The radial ports 33a provide escape ways for any fluid or gas trapped between the sleeve 33 and packer 30 to ensure complete retraction of the packer. The slips are released by further lowering of the mandrel 11 to engage the mandrel shoulder 11d with the upper axial end surface of the slotted sleeve 26. Downwardly directed forces on the mandrel 11 are then employed to slide the slip spreader 25 below the slips 2] permitting them to retract radially under the biasing force of the spring 22. FIG. 7 illustrates the tool 10 in its fully released condition.

During the described setting and release operations, movement of the mandrel knob l lfwas confined in the longitudinal control sleeve slot'14b. Continued lowering of the mandrel 11 after release of the slips 21 moves the mandrel knob 11f through the control sleeve slot 140 and into the stop 14d. Subsequent raising of the mandrel draws the knob 11f upwardly through the slots Me and 14finto the stop 14g. With the knob 11f in the latter position, the upper assembly 13 is raised by continued upward movement of the wire line W and attached mandrel 11 to prevent resetting of the packer 30 and slip 21 as the tool is withdrawn from the conduit C.

The control sleeve slot paths 14h and l4j and stop 141' permit the tool to be reset any number of times. Thus, with the knob 11fin stop 14g, the tool 10 may be reset at a higher location in the conduit by raising the wire line W until the desired depth is reached and thereafter lowering the mandrel knob 1 lfto move it through the slot 14h and into the stop 141'. Subsequent raising of the mandrel 1] draws the knob llfthrough the slot 14j back to slot 14b. The previously described setting and retrieving procedure may then be repeated. Where the tool is to be reset at a deeper location, it is lowered to the required depth by resting the knob llfin the stop lli causing the tool to move downwardly to the desired location. Subsequent raising of the mandrel then positions the knob llfin slot 14b. The illustrated slot path construction also permits the tool 10 to be raised or lowered any number of times without setting either the slips or packer. It should be observed that in resetting of the tool after previous shearing of the pins 26b, the upward movement of the mandrel 11 is transmitted through the backup body 36 and the mid assembly 23 to draw the slip spreader 25 into engagement with the stationary slips 21. It should also be noted that when flowing pressure is to be tested or when otherwise desired, the slips 21 of tool 10 may be anchored in the conduit without severing shear pins 26b and hence without expanding the packer 30. In the latter event, the slips 2] may be released and the tool may be moved through the conduit by moving the knob llfinto the stops 14d or 14g depending upon whether the tool is to be lowered or raised.

FIG. 8 illustrates a second form of the present invention indicated generally at 110 which is designed to equalize or alter pressure induced forces acting on the central mandrel. The upper portion of the tool 110 is identical to the form of the invention illustrated in FIGS. 1-7 and the setting and retrieving functions previously described are equally applicable. The tool 110 has been modified by replacing the lower assembly 32 with a second assembly 132 which includes a spacer 139 which is threadedly secured to a chamber housing 140. Radial ports 34b may be provided through the spreader 34 for a purpose to be hereinafter described. The mandrel 11 has been modified by adding a mandrel exte'nsion section 111 having a radially enlarged section 111a and a reduced section 11b. The lower end of extension 111 is threadedly engaged with the backup body 36 and an O-ring seal 141 is disposed between the mandrel extension 111 and the mandrel section 11b to protect the internal components of the mandrel from moisture.

The described modification forms a pressure equalization chamber 146 about the mandrel with the ends of the chamber being sealed against the extension 111 by axially spaced 0- ring seals 147 and 148. v

As will be described, pressure induced forces on the mandrel 11 are balanced or altered in either axial direction by maintaining the pressure within chamber 146 substantially equal to atmospheric pressure and construction the cross-sectional area of section 111a of extension 111 approximately equal to greater than or less than the combined cross-sectional areas of both section 11112 of the mandrel extension 111 and the enlarged mandrel section 11c By such means, the force required to open the pressure bypass across the set packer may be substantially reduced or eliminated to prevent damage to the tool and to protect equipment secured to the tool.

With the tool in the set position illustrated in FIG. 8, an upwardly directed force is induced in the mandrel 11 at the sealing points of O-rings 35 and 148. When the cross-sectional area of section 111a is equal to the sum of the cross-sectional areas at 11c and 111b, the effect of such upwardly directed forces is substantially cancelled by the oppositely directed force acting on the mandrel at the larger diameter O-ring 147. Where a resultant downward mandrel force is desired, the cross-sectional area of 111a is made larger than the sum of the cross-sectional areas at 11c and lllb. In the latter event, the bypass of the tool may be opened automatically upon release of the tension in the wire line W by omitting the shear pins 34a. In many applications, a hydrostatic head exists above the set packer 30 resulting in a reduction of the pressure differential across the packer and thereby requiring appropriate modification of the cross-sectional areas at 111a and l11b as required for a net upwardly or downwardly directed force on the mandrel. If the tool is to remain in its set position without requiring a continuous upward tension by the wire line W, the cross-sectional areas of the extension are designed to provide an upwardly directed force which is greater than the force exerted on the mandrel by virtue of the pressure differential existing at 1 1c. In the latter situation as well as in any application where a net upwardly directed force is desired, the cross-sectional area of mandrel section 111a is made less then the total cross-sectional areas of the mandrel at 11c and lllb. Thus in general terms, the magnitude and direction of the net, pressure induced force acting on the mandrel are functions of the magnitude of the pressure differential existing across the set packer 30 and of the relationship between the cross-sectional areas of the mandrel at 110, 1110 and lllb. In accordance with the teachings of the present invention, the cross-sectional areas at 11c, 111a and 1l1b may be altered as desired to reduce pressure induced forces to substantially zero or to provide a net upwardly or downwardly directed force on the mandrel.

Where a net upwardly directed pressure induced force is present on the mandrel, the opening of the pressure bypass is similar to that described previously with reference to FIGS. 1- 7 and is effected by moving the mandrel l1 downwardly to sever the shear pins 34a and move the enlarged mandrel section llc out of sealing engagement with the valve sleeve 33. The high-pressure gas or fluid below the set packer is then permitted to enter the radial ports 34-b, travel through the sleeve 33 and exit through the slots 26a to equalize the pressure above and below the packer 30.

While the present invention has been described with specific reference to applications where the highest pressure exists below the packer 30, it will be appreciated that the tools 10 or 110 need only be reserved for applications where the pressure above is greater than that below the packer. In the latter event, the wire line assembly W is secured to the backup body 36 and the equipment E is secured to the threads formed at the top of mandrel section Ila.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

lclaim:

l. A shutin tool for forming a seal in a tubular conduit comprising:

a. an axially extending mandrel having first and second axi ally spaced ends;

b. anchoring means carried about said mandrel and operable by said mandrel for anchoring said tool within the tubular conduit;

retaining means carried with said anchoring means for holding said anchoring means stationary with respect to the tubular conduit while the mandrel is moved relative to said anchoring means;

d. sealing means carried about said mandrel and operable by said mandrel for engaging and forming a pressure seal with the tubular conduit;

radially expandable packer means included with said sealing means for engaging and sealing with the internal wall of the conduit;

f. packer spreader means included with said sealing means operable by said mandrel to engage and radially expand said packer means;

g. first securing means connecting said packer spreader means and said mandrel for securing said packer spreader means and said packer means against axial movement relative to each other while said mandrel operates said anchoring means to anchor said tool within the tubular conduit; and

h. bypass means dispose between said mandrel and said sealing means and operable by said mandrel for opening or closing a pressure bypass path communicating with the internal conduit areas axially above and below said sealing means.

2. The shutin tool as defined in claim 1 further including force altering means for altering the effect of pressure induced, axially directed forces acting against said mandrel when said sealing means is in pressure sealing engagement with the well conduit.

3. The shutin tool as defined in claim 2 wherein said retain ing means includes friction drag means for engaging the internal wall of the conduit to resist axial movement of said anchoring means through the conduit.

4. The shutin tool as defined in claim 2 wherein:

a. mandrel sealing means engage said mandrel for forming a seal between said mandrel and said conduit engaging sealing means;

b. said force altering means includes a tubular housing having first and second axially spaced ends disposed about said mandrel with said first housing end being positioned between said mandrel sealing means and said second housing end;

c. first and second housing sealing means are disposed between said housing and said mandrel adjacent said first and second housing ends respectively for forming a sealed annular chamber about said mandrel;

d. holding means are included for holding said housing substantially stationary with respect to said conduit engaging sealing means when said conduit engaging sealing means is in pressure sealing engagement with the conduit; and

e. the cross-sectional area of said mandrel adjacent said first housing sealing means is substantially equal to greater than or less than the sum of the cross-sectional areas of said mandrel adjacent said mandrel sealing means and said second housing sealing means for altering pressure induced axially directed forces exerted on said mandrel when said conduit is sealed by the tool whereby such forces are substantially balanced, or tend to force said mandrel away from or toward said conduit engaging sealing means respectively.

5. The shutin tool as defined in claim 2 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends.

6. The shutin tool as defined in claim 5 wherein said retaining means includes friction drag means for engaging the internal wall of the conduit to resist axial movement of said anchoring means through the conduit.

7. The shutin tool as defined in claim 1 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends.

8. The shutin tool as defined in claim 3 wherein said retaining means includes friction drag means for engaging the internal wall of the conduit to resist axial movement of said anchoring means through the conduit.

9. The shutin tool as defined in claim 1 wherein said retaining means includes friction drag means for engaging the internal wall of the conduit to resist axial movement ofsaid anchoring means through the conduit.

10. The shutin tool as defined in claim 9 wherein said anchoring means includes:

a. radially expandable metal slip means for engaging and locking with the internal wall of the conduit;

b. slip spreader means operable by said mandrel to engage and radially expand said slip means into engagement with the conduit; and

c. biasing means for biasing said slip means radially inwardly to a normally retracted position.

ll. The shutin tool as defined in claim 10 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends.

12. The shutin tool as defined in claim 11 further including force altering means for altering pressure induced, axially directed forces acting against said mandrel when said sealing means is in pressure sealing engagement with the well conduit.

13. The shutin tool as defined in claim 10 wherein:

a. said drag means and slip means are mounted about said mandrel in a first assembly;

b. said slip spreader means and said packer means are mounted about said mandrel in a second assembly; and

c. said packer spreader means is mounted about said mandrel in a third assembly.

14. The shutin tool is defined in claim 13 wherein:

a. said first assembly includes a control sleeve surrounding said mandrel with said control sleeve including a slotted pathway for receiving and directing a radial projection extending from said mandrel for selectively transmitting axial motion of said mandrel to said first assembly;

b. said slip means is secured adjacent one end of said first assembly and includes a plurality of metal slip fingers having teeth formed along their radially external areas and a smooth, tapered surface formed along their radially internal areas;

0. said slip spreader means is secured adjacent one end of said second assembly and includes a conical surface adapted to engage and slide under said tapered surfaces of said slip fingers to expand said fingers radially outwardly into engagement with the conduit;

. said packer means is secured adjacent the other end of said second assembly and includes a resilient, tubular cup packer having an axially extending internal opening;

. said third assembly includes a tubular valve sleeve surrounding said mandrel and extending axially from said packer spreader toward said packer;

f. said packer spreader means includes a conical surface extending radially outwardly from the outer surface of said valve sleeve whereby said valve sleeve is operable by said mandrel to slide into said internal opening of said packer and said packer spreader is adapted to engage and expand said packer radially into sealing engagement with the conduit;

g. said bypass means includes first bypass sealing means disposed between said packer and said valve sleeve and second bypass sealing means disposed between said mandrel and said valve sleeve; and

h. said second bypass sealing means is controllable by axial movement of said mandrel to open or close the seal formed between said mandrel and said valve sleeve for opening or closing said pressure bypass path.

15. The shutin tool as defined in claim 14 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends.

16. The shutin tool as defined in claim 13 wherein said first securing means includes first severable shear pin means extending between said second assembly and said mandrel whereby said packer spreader means is prevented from moving axially relative to said packer means until said first shear pin means has been severed.

17. The shutin tool as defined in claim 16 further including second releasable securing means including second severable shear pin means securing said mandrel to said packer spreader means whereby said mandrel is prevented from moving axially relative to said packer spreader means until said shear pin means has been severed.

18. The shut-in tool as defined in claim 1 wherein:

a. said sealing means includes a resilient, tubular cup packer having an axially extending internal opening;

b. a packer spreader means is carried about said mandrel and includes a conical surface for engaging and radially expanding said packer;

c. said bypass means includes a tubular valve sleeve carried about said mandrel and secured to said packer spreader with said valve sleeve being operable by said mandrel to slide into said internal opening of said packer;

d. said bypass means further includes first bypass sealing means disposed between said packer and said valve sleeve and second bypass sealing means disposed between said mandrel and said valve sleeve; and

e. said second sealing means is controllable by axial movement of said mandrel to open or close the seal formed between said mandrel and said valve sleeve for opening or closing said pressure bypass path.

19. The shutin tool as defined in claim 18 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends.

20. A shutin tool for forming a seal in a tubular conduit comprising:

a. an axially extending mandrel having first and second axially spaced ends;

b. anchoring means carried about said mandrel and operable by said mandrel for anchoring said tool within the tubular conduit;

c. retaining means carried with said anchoring means for holding said anchoring means stationary with respect to the tubular conduit while the mandrel is moved relative to said anchoring means;

d. sealing means carried about said mandrel and operable by said mandrel for engaging and forming a pressure seal with the tubular conduit;

e. force altering means for altering the effect of pressure induced, axially directed forces acting against said mandrel when said sealing means is in pressure sealing engagement with the well conduit; a plurality of moveable, pressure responsive seal means included with said force altering means, said seal means having different effective pressure areas engaging chamber means for imparting an axially directed force on said mandrel in a direction which is determined by the respective sizes and relative axial positions of said movable seal means.

21. The shutin tool as defined in claim 20 wherein:

a. mandrel sealing means engage said mandrel for forming a seal between said mandrel and said conduit engaging sealing means;

b. said force equalizing means includes a tubular housing having first and second axially spaced ends disposed about said mandrel with said first housing end being positioned between said mandrel sealing means and said second housing end;

c. first and second housing sealing means are disposed between said housing and said mandrel adjacent said first and second housing ends respectively for forming a sealed annular chamber about said mandrel;

d. holding means are included for holding said housing substantially stationary with respect to said conduit engaging sealing means when said conduit engaging sealing means is in pressure sealing engagement with the conduit; and

e. the cross-sectional area of said mandrel adjacent said first housing sealing means is substantially equal to greater than or less than the sum of the cross-sectional areas of said mandrel adjacent said mandrel sealing means and said second housing sealing means for altering pressure induced axially directed forces exerted on said mandrel when said conduit is sealed by the tool whereby such forces are substantially balanced, or tend to force said mandrel away from or toward said conduit engaging sealing means respectively.

22. The shutin tool as defined in claim 21 wherein said retaining means includes friction drag means for engaging the internal wall of the conduit to resist axial movement of said anchoring means through the conduit.

23. The shutin tool as defined in claim 22 further including at least one insulated electrical conducting means extending axially through said mandrel for providing an insulated electrical pathway between said first and second axially spaced mandrel ends. 

